Antenna system



Nov. 20, 1934. BEL-| |N| 1,981,024

ANTENNA SYSTEM Filed Oct. 23. 1931 DETECTOR l: AMPLIFIER v APPARATUS fi: 355 25 g INVENTOR ETTORE mu 1 BY (g A'JTORNEY Patented Nov. 20, 1934 ori PATEN ANTENNA SYSTEM Ettore Bellini, Paris, France, assignor to Compagnie Generals de Telegraphic, Sans Fils,

Paris, France, a corporation of France Application October 23, 1931, Serial No. 570,563 In France October 31, 1930 I 4 Claims.

It is a well known fact that the reception in radio telegraphy and telephony is greatly inconvenienced by the presence of strays either of an atmospheric or an industrial origin. In fact, sometimes reception is rendered difficult and occasionally even impossible.

These disturbances due to strays are obviated in a system constructed in accordance with this invention which comprises a plurality of circuits wherein the aerial circuit is designed to oscillate only at frequencies which differ from the working frequencies. The working frequencies are those which are inherent in or natural to one or more of the other circuits comprising the system. Inasmuch as the major part (or nearly all) of the strays is of aperiodic character the strays will cause shock excitation in this aerial and set up therein frequencies differing from the working frequencies. The energy of the strays will thus be transformed into heat at frequencies other than the working frequency which, as a consequence, will be free from strays and be taken from another circuit of the assembly.

Referring to the drawing, Figures 1 and 2 disf close fragmentary portions of complete radio signaling systems which are illustrated herein for theoretical considerations and which will be discussed later. Figure 3 discloses a particular circuit arrangement embodying the principles of this invention, and Figure 4 is a modification of the arrangement of Figure 3.

The basic idea underlying the invention is as follows:

The applicant has demonstated (see Electrician, London, July 16, 1920) that when having three oscillating circuits each one of which is tuned separately to one and the same frequency n, when they are coupled as shown in Figure 1, there is obtained: (1) In the outer circuits 1 and 3: the three frequencies:

where K is the coupling factor which is assumed to be the same between the circuits 1 and 2 and 2 and 3; and

(2) In the intermediate or middle circuit 2 only the frequencies m and m.

If the intermediate circuit is aperiodic (Fig.

2), the outers have the frequencies n and whereas the intermediate circuit 2 carries only J frequency 114.

Now, this discovery was extended by the inven tor (see Electrician, May 12, 1922) to any number at all of coupled oscillatory circuits, the results thereof briefly being as follows:

(1) The number of resultant frequencies is equal to the number of coupled circuits.

(2) When the number of circuits is even, all of the frequencies are found in all of the circuits.

(3) When the number of circuits is odd, the outer circuits only have all of the frequencies, the second and the next to the last circuits present m-l frequencies; the third and the second circuit before the last presents m-2 frequencies, and so on so that the central circuit presents only (m1)/2 frequencies, m being the number of circuits.

(4) When there is an uneven aggregate number of circuits, it is only the circuits of the order 1, 3, 5 (m 1) ("m-2) that have the frequency common to all of the circuits prior totheir coupling.

Now, according to the present invention, one of the circuits involving a limited number of frequencies is made to play the part of the aerial wire (in an odd number of circuits), while for the working frequency is chosen one of those that is not natural to the circuit playing the part of the aerial. It follows that the atmospheric or industrial strays which cause oscillations in the loop or antenna by virtue of shock will have no effect upon the frequency of the incoming or signal wave, as they will generate oscillations of a frequency different from that of the signals.

Figure 3 is an embodiment of the basic idea of the invention shown by Way of example. Loop 1 and the circuits 2, 3, and 4 are separately tuned to one and the same wave-length, say 600 meters. The coupling between the circuits 1 and 2 and between circuits 1 and 3 is strong or 95 close, while the coupling between 3 and 4 is loose.

After coupling, the circuit 1, for instance, will present two frequencies corresponding to wavelengths 220 and 800 meters, whereas the circuits 2 and 3 present the frequencies corresponding to wave-lengths 220, 600 and 800 meters. Hence, the 600 meter wave picked up by the circuit 4 will be free from strays.

' It is to be noted that in relation to the working wave of 600 meters, the loop will operate as an aperiodic or non-tuned loop or coil.

Reception by loop or antenna being aperiodic or not tuned is effected nowadays in certain special cases, for instance, in connection with the Bellini-To'si radio-goniometer system. If the coupling between the aperiodic coils or the antenna and the secondary oscillation circuit is adequately close, the loss in sensitiveness in comparison with a loop or an antenna that is tuned will be insignificant.

Figure 4 where corresponding elements are indicated by the same reference numerals as in Figure 3 shows by Way of example one of the ways of applying the basic idea of this invention to a vertical antenna. The antenna or the loop may be aperiodic in accordance with the diagram shown in Figure 2.

Instead of using three circuits, recourse could be had to five, seven, etc. (provided that the number is always odd), using as a loop or antenna either the middle circuit of the chain or one of those others which do not present the working frequency or several of these latter. Certain ones of these circuits may be aperiodic in accordance with the scheme shown in Figure 2. It is moreover not indispensable that the circuits should carry the same frequency prior to their being coupled nor that their aggregate number should be odd; in fact, the basic principle of the invention is in general to utilize as the working frequency one of those frequencies which do not happen to be present in the circuit which constitutes the aerial.

The magnetic couplings existent between the circuits indicated in the illustrations may be replaced, Wholly or partly, by some other mode of coupling, more particularly speaking by a condenser or electric coupling.

By using a sufficiently great number of circuits, it is feasible to simultaneously receive by distinct receivers a plurality of communications sent over different frequencies.

It is to be noted that the combinations of circuits investigated between 1920 and 1922 in The Electrician are not the only ones to be used in forming circuit arrangements falling Within the scope of the present invention. In fact, it is possible to conceive combinations of aperiodic or oscillatory circuits, in which the latter oscillate at suitable frequencies, either pair or odd in number, being in more or less close or loose inter-coupling relationship and which will satisfy like the former the conditions of the present invention.

What is claimed is:

1. An anti-stray radio receiver system comprising an odd number of closely coupled oscillation circuits arranged in cascade, at least two of said oscillation circuits being tuned to the signal frequency to be received, and a utilization circuit arranged in loose coupling relationship with the last'of said oscillation circuits.

2. An anti-stray radio receiving system having, in combination, an odd-number of closely coupled oscillation circuits arranged in cascade, of which the center oscillation circuit comprises an energy. pick-upcollector, at leasttwo of said oscillation circuits being tuned to the signal frequency to be received, and a utilization circuit arranged in loose coupling relationship with the last of said oscillation circuits.

3. .An anti-stray radio receiving system having, in combination, an odd number of closely coupled oscillation circuits arranged in cascade and tuned to the frequency to be received, of which the centralcircuit comprises an energy pick-up collector, and a utilization circuit arranged in loose coupling relationship with the last of said oscillation circuits.

4. An anti-stray radio receiving system hav, ing, in combination, an odd number of closely coupled oscillation circuits arranged in cascade, of which the central oscillation circuit comprises an aperiodic energy pick-up collector, and a utilization circuit arranged in loose coupling relationshipwith the last of said oscillation circuits.

' E'ITORE BELLINI. 

